[ Identification | Description | Examples | Input parameters | Links ]

The ESS_butterfly_Guide_curved_test Instrument

Test instrument for the updated BF1 butterfly moderator design including a simple guide.

Identification

• Site: ESS
• Author: Peter Willendrup
• Origin: ESS
• Date: 2016-09-26

Description

Test instrument for the updated BF1 butterfly moderator design including a simple guide with 10 m straight flight-path followed by a 50 m curved guide.

The below example gives a 50-50 (statistics-wise) cold/thermal beam at beamline S2.
Example: sector=S beamline=2 cold=0.5 Detector: Monitor2_xy1_I=1.59e+11

Use the ESS_butterfly_MCPL_test instrument for direct comparison with MCPL-based source descriptions.

Examples

(Test cases in bold)

• Test: sector=S beamline=2 cold=0.5 Detector: Monitor2_xy1_I=1.59e+11

Input parameters

Parameters in boldface are required; the others are optional.

Name	Unit	Description	Default
sector	str	Defines the 'sector' of your instrument position. Valid values are "N","S","E" and "W"	"S"
beamline	1	Defines the 'beamline number' of your instrument position. Valid values are 1..10 or 1..11 depending on sector	2
Lmin	AA	Minimum wavelength simulated	0.2
Lmax	AA	Maximum wavelength simulated	20
c_performance	1	Cold brilliance scalar performance multiplicator c_performance > 0	1
t_performance	1	Thermal brilliance scalar performance multiplicator t_performance > 0	1
index	1	Target index for source focusing. Defaults to illuminate the "cold collimated" brilliance monitor, thereby suppressing "dist"	0
dist	m	Distance from origin to focusing rectangle; at (0,0,dist) - alternatively use target_index	2
cold	1	Defines the statistical fraction of events emitted from the cold part of the moderator	0.5
Yheight	m	Defines the moderator height. Valid values are 0.03 m and 0.06 m	0.03
delta	m	Parameter that allows to scan "collimator" position	0
n_pulses	1	Number of pulses to simulate	1
allmons	1	Flag to include also debugging-monitor output	0

Links

• Source code for ESS_butterfly_Guide_curved_test.instr.
• Benchmarking website available at http://ess_butterfly.mcstas.org

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[ Identification | Description | Examples | Input parameters | Links ]

Generated for mcstas 3.10.2

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Last Modified: Tue Nov 3 18:52:15 2026